4 HORTICULTURAL SOCIETY OF NEW YORK. 



cess, to compensate for the numerous failures which the worker 

 must necessarily encounter. 



Two main considerations confront us in the problems of 

 acclimatization. First, a careful examination reveals the fact 

 that nearly every species in the wider usage of the term in- 

 cludes several races or elementary species, which bear different 

 hereditary quaflities as to hardiness, capability for accommoda- 

 tion, rapidity of growth and productiveness. Careful culture 

 enables a comparison to be made among a group of such forms 

 and to select those which bear the desired qualities to make an 

 introduction or acclimatization operation successful. Perhaps 

 the necessary qualities may be discerned in separate races of ele- 

 mentary species, and by hybridizations these qualities are 

 brought together into races or species capable of meeting the 

 conditions to be encountered. To recount, or even adequately 

 illustrate the triumphs and accomplishments of the horticultur- 

 ist by methods for the most part very crude, during the last 

 century, would be impossible. 



Now, however, by the light of present knowledge, profiting 

 by the splendid results of Nilsson with cereals, all such opera- 

 tions may be carried out with much greater exactitude and much 

 more rapidly than by the old-time method of trial and error, 

 most wasteful of skilled energy and time-consuming in human 

 life. To-day we may expect as much from the breeder in ten 

 years as he might have been able to accomplish in the previous 

 half century. The realization has been tardily reached that if 

 we are to make alterations in the hereditary qualities of the 

 plants useful to us, we must make an accurate analysis to dis- 

 close the constituents of the species with which we are dealing, 

 and having this information we may proceed with the exactitude 

 of the chemist making compounds and extractions in his labora- 

 tory. 



With so much to our credit in the way of advance made in 

 knowledge of the nature of the plant and its behavior, the other 

 important task which confronts us is that of making a similarly 

 exact study of climate and of all of the factors which constitute 

 the complex set of conditions which we term environment. 



A simple analysis of the relations of a plant to external 



